1. Field of the Invention
The present invention relates to a server device, a mobile communications terminal, an information transmitting system and an information transmitting method, and more particularly to a server device which transmits pattern data used for the detection of computer viruses to a mobile communications terminal, an information transmitting system, an information transmitting method, and a mobile communications terminal which receives pattern data transmitted from the server device.
2. Description of the Related Art
The current development of mobile communications technology has been remarkable, and our daily life activities are made increasingly convenient in the current age of the “information society”. For example, as a result of the spread of the internet, useful application programs and data files can easily be downloaded into terminal devices such as personal computers or the like, and can be utilized.
However, items that are downloaded into terminal devices via the internet are not always limited to useful application programs and data. Specifically, computer viruses that destroy useful application programs and data also frequently invade terminal devices via the internet.
For example, computer virus detection techniques using pattern matching systems are known as techniques for detecting whether or not a computer virus has invaded a terminal device. In such techniques, a database accommodating characteristic data sequences (hereafter referred to as “pattern data”) contained in computer viruses is transmitted to a terminal device from a server device and stored in the terminal device, and the abovementioned pattern data is compared with application programs and data that are similarly stored in the terminal device. As a result, in cases where application programs or data contain the abovementioned pattern data, it is judged that these application programs or data contain a computer virus. In cases where computer virus detection techniques using pattern matching systems are utilized, it is necessary that the abovementioned database be successively updated to the most recent version in order to increase the probability of detecting computer viruses. Accordingly, when a new type of computer virus is detected, characteristic pattern data contained in this computer virus is transmitted to the terminal device from the server device, and the abovementioned database of the terminal device is updated.
However, the following problems have been encountered in cases where the abovementioned conventional technique is used to detect computer viruses in a mobile communications terminal such as a portable telephone. Specifically, in the case of such a mobile communications terminal, the memory capacity and CPU capacity are insufficient compared to those of a terminal device such as a personal computer or the like. Accordingly, it is difficult to store all of the abovementioned database in a mobile communications terminal, and to compare all of the pattern data contained in this database with the application programs and data in the mobile communications terminal in a comprehensive manner. Furthermore, while terminal devices such as personal computers or the like and server devices are usual connected by a wire circuit, mobile communications terminals and server devices are connected by a wireless circuit. Accordingly, in cases where all of the abovementioned database is transmitted to a mobile communications terminal from a server device, a very large wireless resource is consumed. For such reasons, the detection of computer viruses in mobile communications terminals cannot be efficient performed in the case of the abovementioned conventional technique.